Hi,
I had the same problem with a Nokia 5300 xpress music.
I was able to fix this by removing the back cover, unscrewing the 2 T6 screws to allow removal of the back and I then saw that the flat terminating end of the ribbon cable was disconnected; I just pushed it back into its socket and now the screen works.
I think the problem would have been caused by the phone being dropped and this allowed the slight displacement of the ribbon cable from its very shallow socket.
Scott
April 2010